POS0994-HPR CONVERGENT VALIDITY OF SIX MINUTE STEPPER TEST TO EVALUATE FUNCTIONAL EXERCISE CAPACITY IN PATIENTS WITH SYSTEMIC SCLEROSIS
Authors: S. Bayram, N. G. Tore, G. G. Pala, I. Vasi, A. Tufan, D. Oskay
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Exercise capacity is impaired in systemic sclerosis (Ssc) patients due to respiratory and cardiovascular involvements, muscle weakness, arthritis/arthralgia, and joint contractures. Various tests are employed to assess submaximal and maximal exercise capacity in Ssc. Maximal exercise tests, the gold standard for assessing exercise capacity, are challenging since they require expensive equipment and qualified personnel. The 6‑minute walk test (6MWT) is a commonly used submaximal field exercise test to assess functional exercise capacity and is shown to be associated with the prognosis in SSc patients. The 6-minute stepper test (6MST) is a low-cost, space-friendly submaximal field test that has been demonstrated to be valid, reliable, and sensitive in assessing exercise capacity in various diseases. <h3>Objectives</h3> No research hasn't been done on the validity of 6MST in Ssc patients. Given that it mimics stair climbing, the 6MST may be more helpful in evaluating lower extremity functions in Ssc. Therefore, the aims of this study were (1) to assess the convergent validity of the 6MST in Ssc; and (2) to compare physiological responses, dyspnea and fatigue perception obtained in 6MST and 6MWT. <h3>Methods</h3> Thirty female patients with Ssc (52.13 + 11.83 years) were enrolled. Demographic and clinical characteristics were recorded. 6MST was performed twice (6MST-1 and 6MST-2) to eliminate learning effect and because the hydraulic jacks become more flexible after they have warmed up. The 6MST-2 was performed after a resting time of at least 20 minutes after 6MST-1. The 6MWT was carried out three hours after the 6MST-2 to minimize fatigue on outcomes. To test the convergent validity of the 6MST, correlation between the 6MWT and 6MST-2 was assessed. In addition, the association between 6MST and the level of physical activity, dyspnea and fatigue severity in Ssc patients was investigated. International Physical Activity Questionnaire (IPAQ), modified British Medical Research Council Questionnaire (mMRC) dyspnea scale, Fatigue Severity Scale (FSS) were used to assess physical activity, dyspnea and fatigue severity, respectively. The heart rate (HR), peripheral oxygen saturation (SpO<sub>2</sub>), blood pressure (BP), modified Borg scale score for dyspnea, general and leg fatigue were recorded before and after 6MWT and 6MST. Changes between their final and initial values (Δ) for HR, SpO<sub>2</sub>, BP, and modified Borg score were calculated. <h3>Results</h3> The number of steps in 6MST-2 was significantly higher than 6MST-1 (p&lt;0.001). The number of steps in the 6MST-2 was significantly correlated with the distance walked in the 6MWT (r=0.616, p&lt;0.0001). Additionally, significant correlations were observed between 6MST-2 and mMRC dyspnea scale score (r=-0.733, p&lt;0.0001), FSS score (r=-0.575, p≤0.001), IPAQ score (r=0.330, p&lt;0.05). ΔBP, Δdyspnea, Δgeneral and Δleg fatigue perception were higher in the 6MST-2 than the 6MWT (p&lt;0.0001). ΔHR and ΔSpO<sub>2</sub> were similar in 6MST and 6MWT (p&lt;0.05). <h3>Conclusion</h3> The 6MST is a valid test to evaluate functional exercise capacity in Ssc patients. The 6MST might be more appropriate for evaluating perceived exertion, functioning, and lower extremity capacity. To assess the exercise capacity in Ssc patients, 6MST can be done with ease in all settings, including primary care to hospital settings with limited space and home-based telerehabilitation. <h3>References</h3> [1]Cuomo, G., Santoriello, C., Polverino, F., Ruocco, L., Valentini, G., &amp; Polverino, M. (2010). Impaired exercise performance in systemic sclerosis and its clinical correlations. <i>Scandinavian journal of rheumatology</i>, <i>39</i>(4), 330-335. [2]Coquart JB, Lemaître F, Castres I et al. Reproducibility and sensitivity of the 6-minute stepper test in patients with COPD. COPD 2015;12:533–8. [3]Francisco DDS, Martinez L, Terrazas AC et al. Six-minute stepper test in hospitalized elderly patients: convergent validity, test-retest reliability and safety. PLoS One 2020;15:e0241372. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.